I was looking on Don Barne’s site (thanks Don, as many have said, your site is really nice) on the subject of seat belts.  Specifically

 

http://www.lancairlegacy.com/tips_harness.html

 

I downloaded and was browsing through the FAA Advisory Circular (AC) 21-34 concerning seatbelt harnesses, and it seemed to contradict Ron Brice’s note about seatbelts mounted overhead.

 

http://rgl.faa.gov/Regulatory_and_Guidance_Library\rgAdvisoryCircular.nsf/0/5214C6FFB14E1383862569B2005E77F9?OpenDocument

 

(page 26)

 

It says that “Low attachments create spinal compression” and high attachments cause additional structural loads and poor restraint, not the other way around as Rice’s note suggests.

 

It seems the system Rice put in, unless greater than -8 degrees tangent with the top of your shoulder would be the dangerous one to your spine, not the overhead (over +30 degrees tangent).

 

Did I miss something?  It seems that the drawback to the overhead isn’t problems with spine crushing; it’s insuring the structure is strong enough to keep the belts in place?  Is this correct?

 

Thanks

Kevin